Far-Ultraviolet Dust Albedo Measurements in the Upper Scorpius Cloud Using the SPINR Sounding Rocket Experiment

The Spectrograph for Photometric Imaging with Numeric Reconstruction (SPINR) sounding rocket experiment was launched on 2000 August 4 to record far-ultraviolet (912-1450 A) spectral and spatial information for the giant reflection nebula in the Upper Scorpius region. The data were divided into three arbitrary bandpasses (912-1029 A, 1030-1200 A, and 1235-1450 A) for which stellar and nebular flux levels were derived. These flux measurements were used to constrain a radiative transfer model and to determine the dust albedo for the Upper Scorpius region. The resulting albedos were 0.28+/-0.07 for the 912-1029 A bandpass, 0.33+/-0.07 for the 1030-1200 A bandpass, and 0.77+/-0.13 for the 1235-1450 A bandpass

Diagnosis of Helicobacter pylori by carbon-13 urea breath test using a portable mass spectrometer

CONTEXT: In the non-invasive detection of markers of disease, mass spectrometry is able to detect small quantities of volatile markers in exhaled air. However, the problem of size, expense and immobility of conventional mass spectrometry equipment has restricted its use. Now, a smaller, less expensive, portable quadrupole mass spectrometer system has been developed. Helicobacter pylori has been implicated in the development of chronic gastritis, gastric and duodenal ulcers and gastric cancer. OBJECTIVES: To compare the results obtained from the presence of H. pylori by a carbon-13 urea test using a portable quadrupole mass spectrometer system with those from a fixed mass spectrometer in a hospital-based clinical trial. METHODS: Following ethical approval, 45 patients attending a gastroenterology clinic at the Royal Liverpool University Hospital exhaled a breath sample into a Tedlar gas sampling bag. They then drank an orange juice containing urea radiolabelled with carbon and 30 min later gave a second breath sample. The carbon-13 content of both samples was measured using both quadrupole mass spectrometer systems. If the post-drink level exceeded the pre-drink level by 3% or more, a positive diagnosis for the presence of H. pylori was made. RESULTS: The findings were compared to the results using conventional isotope ratio mass spectrometry using a laboratory-based magnetic sector instrument off-site. The results showed agreement in 39 of the 45 patients. CONCLUSIONS: This study suggests that a portable quadrupole mass spectrometer is a potential alternative to the conventional centralised testing equipment. Future development of the portable quadrupole mass spectrometer to reduce further its size and cost is indicated, together with further work to validate this new equipment and to enhance its use in mass spectrometry diagnosis of other medical conditions

The Influence of Relative Advantage Towards e-Procurement Adoption Model in Developing Countries: Tanzania Context

The aim of this study was to fill the knowledge gap through assessing the influence of relative advantage towards e-procurement adoption in developing countries, Tanzania in particular. The study adopted positivism philosophy and cross-sectional survey research design. The study also used stratified sampling technique. Sample size was 157. Questionnaires and documentary review were used for data collection. The collected data were analysed by using Partial Least Squares Structural Equation Modelling with the help of SmartPLS 3 software. Findings reveal that in the presence of attitude, relative advantage has direct and indirect influences towards e-procurement adoption. Grounding on the theoretical and empirical gaps, the hypothesized relationships of the determinants of new technology (relative advantage and attitude) have therefore filled these gaps which leads to the theoretical, empirical and practical contributions.The study recommends attention to be paid for relative advantage towards e-procurement adoption in Tanzania and in all developing countries which intend to adopt new technologies in public sector

Contextual factors among indiscriminate or larger attacks on food or water supplies, 1946-2015

This research updates previous inventories of malicious attacks on food and water to include data from 1946 through mid-2015. A systematic search of news reports, databases and previous inventories of poisoning events was undertaken. Incidents that threatened or were intended to achieve direct harm to humans, and that were either relatively large (number of victims > 4 or indiscriminate in intent or realisation were included. Agents could be chemical, biological or radio-nuclear. Reports of candidate incidents were subjected to systematic inclusion and exclusion criteria as well as validity analysis (not always clearly undertaken in previous inventories of such attacks). We summarise contextual aspects of the attacks that may be important for scenario prioritisation, modelling and defensive preparedness. Opportunity is key to most realised attacks, particularly access to dangerous agents. The most common motives and relative success rate in causing harm were very different between food and water attacks. The likelihood that people were made ill or died also varied by food/water mode, and according to motive and opportunity for delivery of the hazardous agent. Deaths and illness associated with attacks during food manufacture and prior to sale have been fewer than those in some other contexts. Valuable opportunities for food defence improvements are identified in other contexts, especially food prepared in private or community settings

Searching for Far-Ultraviolet Auroral/Dayglow Emission from HD209458b

We present recent observations from the HST-Cosmic Origins Spectrograph aimed at characterizing the auroral emission from the extrasolar planet HD209458b. We obtained medium-resolution (R~18-20,000) far-ultraviolet (1150-1700A) spectra at both the Phase 0.25 and Phase 0.75 quadrature positions as well as a stellar baseline measurement at secondary eclipse. This analysis includes a catalog of stellar emission lines and a star-subtracted spectrum of the planet. We present an emission model for planetary H2 emission, and compare this model to the planetary spectrum. No unambiguously identifiable atomic or molecular features are detected, and upper limits are presented for auroral/dayglow line strengths. An orbital velocity cross-correlation analysis finds a statistically significant (3.8 sigma) feature at +15 (+/- 20) km/s in the rest frame of the planet, at 1582 A. This feature is consistent with emission from H2 B-X (2-9) P(4) (lambda_{rest} = 1581.11 A), however the physical mechanism required to excite this transition is unclear. We compare limits on relative line strengths seen in the exoplanet spectrum with models of ultraviolet fluorescence to constrain the atmospheric column density of neutral hydrogen between the star and the planetary surface. These results support models of short period extrasolar giant planets with weak magnetic fields and extended atomic atmospheres.Comment: Accepted to ApJ. 12 pages, 5 figures, 4 table

Photodégradation de composites constitués de polyéthylène haute densité et de bagasse délignifiée

Les composites bois/polymère sont généralement constitués d'un mélange de bois et de résines plastiques. D'autres matériaux lignocellulosiques peuvent également être utilisés tels que des coproduits agricoles comme la balle du riz, le lin, la bagasse, etc. Au cours des dernières décennies le bois composite a trouvé sa propre place dans les marchés des produits à base de bois grâce à sa facilité d'entretien et à sa grande longévité. La lignocellulose rajoutée à la résine plastique améliore le module d'Young et la résistance à l'étirement comparé au plastique seul [1]. Le bois composite est aussi connu comme un produit recyclable et respectueux de l'environnement. Le bois composite subit la photodégradation quand il est exposé à l'extérieur ce qui provoque la décoloration et la perte de propriétés mécaniques

Observations of Mass Loss from the Transiting Exoplanet HD 209458b

Using the new Cosmic Origins Spectrograph (COS) on the {\it Hubble Space Telescope (HST)}, we obtained moderate-resolution, high signal/noise ultraviolet spectra of HD 209458 and its exoplanet HD 209458b during transit, both orbital quadratures, and secondary eclipse. We compare transit spectra with spectra obtained at non-transit phases to identify spectral features due to the exoplanet's expanding atmosphere. We find that the mean flux decreased by $7.8\pm 1.3$% for the C II 1334.5323\AA\ and 1335.6854\AA\ lines and by $8.2\pm 1.4$% for the Si III 1206.500\AA\ line during transit compared to non-transit times in the velocity interval --50 to +50 km s$^{-1}$. Comparison of the C II and Si III line depths and transit/non-transit line ratios shows deeper absorption features near --10 and +15 km s$^{-1}$ and less certain features near --40 and +30--70 km s$^{-1}$, but future observations are needed to verify this first detection of velocity structure in the expanding atmosphere of an exoplanet. Our results for the C II lines and the non-detection of Si IV 1394.76\AA\ absorption are in agreement with \citet{Vidal-Madjar2004}, but we find absorption during transit in the Si III line contrary to the earlier result. The $8\pm 1$% obscuration of the star during transit is far larger than the 1.5% obscuration by the exoplanet's disk. Absorption during transit at velocities between --50 and +50 km s$^{-1}$ in the C II and Si III lines requires high-velocity ion absorbers, but models that assume that the absorbers are high-temperature thermal ions are inconsistent with the COS spectra. Assuming hydrodynamic model values for the gas temperature and outflow velocity at the limb of the outflow as seen in the C II lines, we find mass-loss rates in the range (8--40)$\times 10^{10}$ g s$^{-1}$.Comment: 25 pages, 4 figures, Astrophysical Journal in pres

Stakeholders’ Perception on Critical Success Factors Influencing Electronic Procurement Adoption in Developing Counties: Experience from Tanzania

The general objective of this study was to examine the stakeholders’ perception on critical success factors influencing Tanzania National electronic Procurement System adoption in public sector. The specific research objectives of the study were to: evaluate the perceived influences of legal framework, performance expectancy, relative advantage and attitude   towards Tanzania National Electronic Procurement System   implementation. The study adopted positivism philosophy and cross-sectional survey research design. The study also used stratified sampling technique. Sample size was 157 respondents. A questionnaire with closed ended questions and documentary review were used for data collection. The collected data were analyzed using Partial Least Squares Structural Equation Modelling with the help of SmartPLS 3 software. Findings reveal that all critical success factors were perceived the same by stakeholders (procurement experts and suppliers) towards Tanzania National Electronic Procurement System adoption. The study concludes that there is no significant difference with regard to stakeholders’ perception on critical success factors influencing Tanzania National electronic Procurement System adoption. The study recommends paying attention to relative advantage, performance expectancy and legal framework to significantly change the mindset of all stakeholders in the country in supporting of Tanzania National Electronic Procurement System implementation

Production of rotenoids by heterotrophic and photomixotrophic cell cultures of Tephrosia vogelii

Les roténoïdes, composés dérivés de la voie du métabolisme phénylpropanoïde, sont en grande partie accumulés dans les feuilles de "Tephrosia vogelii$. Des cultures de suspensions cellulaires hétérotrophes et photomixotrophes de cette plante tropicale ont été obtenues. Les lignées cellulaires sont toutes deux capables de produire des roténoïdes, mais une production spéciale est observée dans chaque type de culture cellulaire. La lignée cellulaire photomixotrophe accumulait de la roténone et de la dégueline, et la lignée cellulaire hétérotrophe produisait essentiellement de la dégueline et de la téphrosine. (Résumé d'auteur